BENDIX SD-13-4958 ユーザーズマニュアル

Supply Port

(Casting has

“1, SUP”)

Exhaust Port

(Body has

“3, EXH”)

Supply 

Port

(Casting has 

“1, SUP”)

Exhaust Port

(Body has “3, EXH”)

Electrical 

Connector

 Mounting Holes 

(.33" Diameter 

Through Body)

Electrical 

Connector

Delivery Port

(Casting has

“2, DEL”) 

The Bendix

®

 M-40QR

™

 (quick release) and M-40HF

™

 (high 

flow) pressure modulator valves (PMVs) are high-capacity, 

on/off air valves that incorporate a pair of electrical 

solenoids for control.  See Figure 1. The solenoids provide 

the  electro-pneumatic  interface  between  the  vehicle’s 

electronic control system and the air brake system.  For 

example, the PMV is used to control the braking function 

of service actuators during antilock activity.  

The modulator consists of a die cast metal and plastic body 

that houses one normally-open solenoid, one normally-

closed solenoid, and an inlet and exhaust diaphragm 

valve.  A three-pin weather-resistant electrical connector 

is an integral part of the modulator solenoid assembly 

and  delivers  the  vehicle  controller’s  commands  to  the 

modulator.  Two mounting holes are provided for frame or 

crossmember mounting of the valve. 

The Bendix M-40QR modulator is the direct replacement 

for the Bendix M-32QR modulator (See Figure 2).  The 

Bendix M-40QR modulator has a bias valve to provide an 

internal quick-release function.

The supply, delivery and exhaust ports on the Bendix M-40 

modulators have embossed identification codes.

1, SUP

Supply

Air enters from a valve (typically 

foot, relay or quick release).

2, DEL

Delivery

Air is delivered to the service 

actuators.

3, EXH

Exhaust

Air is vented to the atmosphere.

Bendix M-40 modulators may be used for various purposes 

on a vehicle including ABS and stability interventions.  In 

applications using these PMVs, an external quick release 

valve may also be required, depending on the system 

design.  Where the modulator is used for individual wheel 

control applications, it is typically the last control valve 

through which air passes on its way to the service brake 

actuator.  See Figure 4 for a typical system schematic.